diff --git a/ChangeLog b/ChangeLog
index c6addbeb5..01fa4779c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -17,6 +17,9 @@ Bugfix
      by inestlerode. #559.
    * Fixed default threading implementation to avoid accidental double
      initialisations and double frees.
+   * Fixed sample application 'programs/pkey/gen_key.c' for builds where the
+     configuration MBEDTLS_PEM_WRITE_C is not defined. Found by inestlerode.
+     #559.
 
 = mbed TLS 2.1.5 branch released 2016-06-28